I posted another post entitled Fetherweight barrel accuracy, and have received some interesting answers to my questions.

But here is the thing. Isn't accuracy really and truly just another word for "repeatability"? I mean, theoretically, if everything is the exact same from shot to shot, then shouldn't the same bullet fired from the same barrel with the same powder and primer go into the same hole?

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Originally posted by 22WRF:
I posted another post entitled Fetherweight barrel accuracy, and have received some interesting answers to my questions.

But here is the thing. Isn't accuracy really and truly just another word for "repeatability"? I mean, theoretically, if everything is the exact same from shot to shot, then shouldn't the same bullet fired from the same barrel with the same powder and primer go into the same hole?

In a purely theoretical world...yes. In the real world...probably not since none of the things you mention can be truly “repeated.â€

No. In science, we learn of inherent variability in physical conditions. the air temp, humidity, humility, barometric pressure, and even altitude affect things, even before accounting for temperature, barrel temp, action temp ammo temp. these things are NEVER the same, and even if most were, the barometer would not be. what you are looking for is a trait of robustness. that is resilience of effect of these micro-differences to make a difference.

For example, we all (almost all) realize that a synthetic stock is more robust against humidity changes than wood. but it is still somewhat affected because humidity affects air pressures, etc.

so in a way repeatability, but more valuable is robustness against the effects of non-repeatability.

A 5-10 mph breeze makes fools of us all. hence the need for constant high level of humility.

Jamie

Since you can't freeze time, nothing is ever repeatable. We can come pretty close, but each shot is a unique event.

jim

quote:

Originally posted by 22WRF:
Isn't accuracy really and truly just another word for "repeatability"? ?

The way that the terms are used about shooting small groups on paper under controlled conditions,YES.

The way one load compares to another shooting for example at varmints under varying con ditions NO. Just my personal definition for what is worth.

If all of the conditions that affect the bullet were exactlty the same the bullet would hit the exact same hole. It's impossible to recreate exactly the same conditions, but we can get close.

As far as repeatability goes, you can minimize some of the factors that affect the bullet by making changes to the rifle. Barrels flex and move when fired. A thick barrel moves less than a thin barrel. This does not make it more accurate, but it lessen the affect that outside influences have on the shot (barrel temp, pressure differences in the stock, etc...). It is easier to get better repeatability with a heavier barrel.

A good way to envision this is to compare it to shooting a rifle offhand. A heavy rifle is more stable. The effect that the wind, and your shooting position etc.. has on the rifle is smaller than with a light rifle. If the heavy rifle moves 1/2" in any given direction while shooting offhand, and the light rifle moves 1.5" it's easier to get the heavy rifle to shoot to the same point of impact because the amount of fluctuation in its position is smaller.

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I mean, theoretically, if everything is the exact same from shot to shot, then shouldn't the same bullet fired from the same barrel with the same powder and primer go into the same hole?

You need to get a copy of THE BULLET'S FLIGHT by Dr. F. W. Mann. That is the question he asked and then set out to find the answer. Though it was written in the early 1900s there is a lot of good stuff in there.

Ray